Case: 21-2168    Document: 35    Page: 1   Filed: 03/06/2023




   United States Court of Appeals
       for the Federal Circuit
                  ______________________

 REGENTS OF THE UNIVERSITY OF MINNESOTA,
                 Appellant

                            v.

                GILEAD SCIENCES, INC.,
                         Appellee
                  ______________________

                        2021-2168
                  ______________________

     Appeal from the United States Patent and Trademark
 Office, Patent Trial and Appeal Board in No. IPR2017-
 01712.
                  ______________________

                  Decided: March 6, 2023
                  ______________________

    EDGAR HAUG, Haug Partners LLP, New York, NY, ar-
 gued for appellant. Also represented by MICHAEL A.
 ALBERT, EDWARD R. GATES, RICHARD GIUNTA, GERALD B.
 HRYCYSZYN, NATHAN R. SPEED, CHARLES T. STEENBURG,
 Wolf Greenfield & Sacks, PC, Boston, MA.

    JOHN SCOTT MCBRIDE, Bartlit Beck LLP, Chicago, IL,
 argued for appellee. Also represented by NEVIN M.
 GEWERTZ, REBECCA HORWITZ; MEG E. FASULO, Denver, CO.
                ______________________

      Before LOURIE, DYK, and STOLL, Circuit Judges.
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 2               REGENTS OF THE UNIVERSITY OF MINNESOTA v.
                                      GILEAD SCIENCES, INC.


 LOURIE, Circuit Judge.
     The Regents of the University of Minnesota (“Minne-
 sota”) appeal from a final written decision of the U.S. Pa-
 tent and Trademark Office Patent Trial and Appeal Board
 (“the Board”) holding that claims 1−9, 11−21, and 23−28 of
 U.S. Patent 8,815,830 are unpatentable as anticipated by
 the asserted prior art. Gilead Scis., Inc. v. Regents of the
 Univ. of Minn., No. IPR2017-01712, 

 (P.T.A.B. May 21, 2021) (“Decision”). For the following rea-
 sons, we affirm.
                        BACKGROUND
     This appeal pertains to an inter partes review (“IPR”)
 in which Gilead Sciences, Inc. (“Gilead”) filed a petition
 challenging claims of the ’830 patent directed to phospho-
 ramidate prodrugs of nucleoside derivatives that prevent
 viruses from reproducing or cancerous tumors from grow-
 ing. Representative claim 1 is presented below:
     1. A compound of formula I:




     wherein:
     R1 is guanine, cytosine, thymine, 3-deazaadenine,
     or uracil, optionally substituted by 1, 2, or 3 U;
     wherein each U is independently halo, hydroxy,
     (C1-C6)alkyl,     (C3-C6)cycloalkyl,   (C1-C6)alkoxy,
     (C3-C6)cycloalkyloxy, (C1-C6)alkanoyl, (C1-C6)alka-
     noyloxy,      trifluoromethyl,      hydroxy(C1-C6)al-
     kyl, -(CH2)1-4P(=O)(ORw)2, aryl, aryl(C1-C6)alkyl, or
     NRxRy;
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    R2 is halo;
    R6 and R7 are independently H or (C1-C6)alkyl;
    R3 is hydroxy;
    R4 is hydrogen, (C1-C6)alkyl, (C3-C6)cycloalkyl,
    aryl, aryl(C1-C6)alkyl, or 2-cyanoethyl;
    R5 is an amino acid;
    X is oxy, thio, or methylene;
    each Rw is independently hydrogen or (C1-C6)alkyl;
    Rx and Ry are each independently hydrogen,
    (C1-C6)alkyl, (C3-C6)cycloalkyl, phenyl, benzyl,
    phenethyl, or (C1-C6)alkanoyl; or Rx and Ry to-
    gether with the nitrogen to which they are attached
    are pyrrolidino, piperidino or morpholino;
    wherein any (C1-C6)alkyl of R1, R4-R7, Rw, Rx, and
    Ry is optionally substituted with one or more halo,
    hydroxy,      (C1-C6)alkoxy,    (C3-C6)cycloalkyloxy,
    (C1-C6)alkanoyl, (C1-C6)alkanoyloxy, trifluorome-
    thyl, azido, cyano, oxo (=O), (C1-C6)alkyl, (C3-C6)cy-
    cloalkyl,              (C3-C6)cycloalkyl(C1-C6)alkyl,
    (C1-C6)alkyl-S-(C1-C6)alkyl-, aryl, heteroaryl, al-
    kyl(C1-C6)alkyl, or heteroaryl(C1-C6)alkyl, or
    NRajRak; wherein each Raj and Rak is independently
    hydrogen, (C1-C6)alkyl, (C3-C6)cycloalkyl, phenyl,
    benzyl, or phenethyl;
    and wherein any aryl or heteroaryl may optionally
    be substituted with one or more substituents se-
    lected from the group consisting of halo, hydroxy,
    (C1-C6)alkyl,   (C3-C6)cycloalkyl,  (C1-C6)alkoxy,
    (C3-C6)cycloalkyloxy, (C1-C6)alkanoyl, (C1-C6)alka-
    noyloxy, trifluoromethyl, trifluoromethoxy, nitro,
    cyano, and amino;
    or a pharmaceutically acceptable salt thereof.
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 4                REGENTS OF THE UNIVERSITY OF MINNESOTA v.
                                       GILEAD SCIENCES, INC.


 ’830 patent at col. 19 ll. 2–47.
     Other claims relate to various subgenera of claim 1, as
 well as administration of the described compounds to treat
 viral infections; but, as the patentability of all the claims
 depends on the patentability of claim 1, they need not be
 recited or described further here.
      Falling within the genus of claim 1 is sofosbuvir, an
 FDA-approved drug marketed by Gilead for treating
 chronic hepatitis C infections. J.A. at 142−43. If the ’830
 patent were found to be valid, it would be a barrier to the
 sale of sofosbuvir without authority. Gilead thus peti-
 tioned for IPR of claims 1−9, 11−21, and 23−28, arguing
 that these claims were not entitled to their claimed priority
 date and were therefore anticipated by U.S. Patent Appli-
 cation Publication 2010/0016251 to Sofia (“Sofia”), which
 was published on January 21, 2010. J.A. at 389−465. Sofia
 is a patent publication owned by Gilead, but that fact is of
 no moment to our decision. During the review, the parties
 agreed that Sofia discloses every limitation of each chal-
 lenged claim. Decision at *5. The result of the IPR thus
 hinged on Sofia’s prior art status and the critical date of
 the ’830 patent.
     The March 28, 2014 application that issued as the ’830
 patent claims priority from four applications filed on the
 dates outlined below. The publication date of Sofia is also
 included in the table below for ease of comparison.
               Description                        Date
  U.S. Provisional App. 60/634,677 (“P1”)      Dec. 9, 2004
  Int. App. PCT/US2005/044442 (“NP2”)          Dec. 8, 2005
  U.S. Patent App.11/721,325 (“NP3”)          June 8, 2007
  Sofia Publication                           Jan. 21, 2010
  U.S. Patent App. 13/753,252 (“NP4”)         Jan. 29, 2013
    In its analysis of the ’830 patent’s priority claims, the
 Board found that NP4 was filed after Sofia was published,
 and that NP3 contained the same disclosure as NP2. The
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 GILEAD SCIENCES, INC.


 Board thus focused its priority analysis on the disclosures
 of NP2 and P1, each of which was filed before Sofia was
 published. Decision at *5. (As NP2 and P1 contain similar
 disclosures in most respects pertinent here, we will refer to
 them henceforth as NP2-P1 without further distinction, ex-
 cept in discussing a claim unique to P1.)
     The Board held that NP2-P1 failed to provide written
 description sufficient to support the ’830 patent’s priority
 claim. According to the Board, these documents contained
 neither ipsis verbis support nor sufficient blaze marks to
 guide the skilled artisan to the claims of the ’830 patent.
 Thus, the challenged claims were not entitled to a priority
 date earlier than their own filing date of March 28, 2014.
 Decision at *16−17. They were thus anticipated by Sofia.
 (The Board did not, in fact, consider whether NP4, filed on
 January 29, 2013, provided written description support for
 the claims of the ’830 patent. However, for reasons that will
 become clear from the discussion below, that does not mat-
 ter to our resolution.)
    Minnesota appealed. We have jurisdiction under
 

(a)(4)(A) and 

(c).
                         DISCUSSION
     We review the Board’s legal determinations de novo, In
 re Elsner, 

 (Fed. Cir. 2004), and the
 Board’s factual findings for substantial evidence, In re
 Gartside, 

 (Fed. Cir. 2000). A finding
 is supported by substantial evidence if a reasonable mind
 might accept the evidence as adequate to support the find-
 ing. Consol. Edison Co. v. NLRB, 

 (1938).
     Minnesota raises three issues on appeal. First, Minne-
 sota contends that the Board erred in holding that NP2-P1
 do not show a written description of what is claimed in the
 ’830 patent. Minnesota also asserts that the Board ran
 afoul of requirements set forth in the Administrative Pro-
 cedure Act (“APA”). Last, Minnesota asserts that it is a
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 6                REGENTS OF THE UNIVERSITY OF MINNESOTA v.
                                       GILEAD SCIENCES, INC.


 sovereign state entity immune from IPR. We address each
 argument in turn.
                                I.
     The written description requirement of 

 reflects the basic premise of the patent system, viz., that
 one discloses an invention and, if it also fulfills the other
 requirements of the statute, one obtains a patent. Quid pro
 quo. Judicial gloss in the case law reflects the need that
 the disclosure show that one actually made the invention
 that one is claiming, i.e., that it possessed the invention as
 claimed. “The purpose of the written description require-
 ment is to prevent an applicant from later asserting that
 he invented that which he did not.” Amgen Inc. v. Hoechst
 Marion Roussel, Inc., 

 (Fed. Cir. 2003).
      Written description of an invention claimed as a genus
 of chemical compounds, as here, raises particular issues be-
 cause, as we have held, written description of a broad ge-
 nus requires description not only of the outer limits of the
 genus but also of either a representative number of mem-
 bers of the genus or structural features common to the
 members of the genus, in either case with enough precision
 that a relevant artisan can visualize or recognize the mem-
 bers of the genus. See Ariad Pharms., Inc. v. Eli Lilly &
 Co., 

, 1350−52 (Fed. Cir. 2010) (en banc). A
 broad outline of a genus’s perimeter is insufficient. See 

      But Minnesota is not arguing in this case that it de-
 scribed a sufficient number of species to constitute a writ-
 ten description of the claimed subgenus.             Rather,
 Minnesota asserts that its earlier NP2-P1 applications lit-
 erally described, or provided blaze marks to, the subgenus
 of the ’830 claims in its broad outlines. The Board held that
 they did not, and we agree.
     The issue here comes down to whether the Board’s find-
 ing that the later-filed ’830 patent is not entitled to the fil-
 ing dates of the earlier filed NP2-P1 applications is
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 REGENTS OF THE UNIVERSITY OF MINNESOTA      v.                 7
 GILEAD SCIENCES, INC.


 supported by substantial evidence. 

 sets
 forth requirements that must be met in order for a patent
 application to benefit from the filing date of an earlier ap-
 plication. To receive “the benefit of the filing date of an
 earlier application under 

, each application
 in the chain leading back to the earlier application must
 comply with the written description requirement of
 

.” Lockwood v. Am. Airlines, Inc., 

 (Fed. Cir. 1997). Original disclosure may not
 be relied upon unless it “constitute[s] a full, clear, concise
 and exact description” of the invention claimed in the pa-
 tent to one of ordinary skill. In re Wertheim, 

,
 538–39 (CCPA 1981).
     Evaluating whether the written description require-
 ment is satisfied involves “an objective inquiry into the four
 corners of the specification from the perspective of a person
 of ordinary skill in the art.” Ariad Pharms., 

. For genus claims, which are present here, we have
 looked for blaze marks within the disclosure that guide at-
 tention to the claimed species or subgenus. In re Ruschig,
 

, 994–95 (CCPA 1967); Fujikawa v. Wattana-
 sin, 

 (Fed. Cir. 1996); see also Purdue
 Pharma L.P. v. Faulding Inc., 

, 1326–27
 (Fed. Cir. 2000). (Here, the parties use language such as
 genus and subgenus to refer to the various disclosures in-
 volved in this inquiry. The disclosure of NP2-P1, being
 broader than claim 1 of the ’830 patent, has a relationship
 of genus to the narrower subgenus of the ’830 patent
 claims. We will use this language of the parties.)
     The primary considerations in a written description
 analysis are factual and must be assessed on a case-by-case
 basis. Vas-Cath Inc. v. Mahurkar, 

 (Fed. Cir. 1991). We thus review the Board’s decision re-
 garding written description for substantial evidence. Gart-
 side, 

.
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 8                 REGENTS OF THE UNIVERSITY OF MINNESOTA v.
                                        GILEAD SCIENCES, INC.


                                A.
      The Board first evaluated whether NP2-P1 provided an
 ipsis verbis disclosure of the subgenus of challenged claim
 1 of the ’830 patent and found that neither application
 does. Minnesota argues on appeal that P1’s claim 47 de-
 scribes challenged claim 1’s exact subgenus. It reasons as
 follows:
     Claim 47, like other claims set forth in P1, defines a
 potential subgenus of substituents for R7. P1 claim 47 re-
 cites:
     47. The compound of any one of claims 1–46
     wherein R7 is hydrogen or (C1-C6)alkyl.
 J.A. at 629; see also, e.g., 

 (defining R7 in claim 48 instead
 as “halo, hydroxy, (C1-C6)alkyl, (C3-C6)cycloalkyl,
 (C1-C6)alkoxy,      (C3-C6)cycloalkyloxy,        (C1-C6)alkanoyl,
 (C1-C6)alkanoyloxy,               trifluoromethyl,          azido,
 cyano, -N(Rz)C(=O)N(Raa)(Rab), -N(Rz)C(=O)ORac, or
 NRadRae”).
      Minnesota asserts that P1 claim 47, combined with P1
 claim 45 (with its disclosure of R6 substituents), P1 claim
 33 (with its disclosure of R5 substituents), P1 claim 21 (with
 its disclosure of the R3 substituent), P1 claim 13 (with its
 disclosure of R2 substituents), P1 claim 2 (with its disclo-
 sure of R1 substituents), and P1 claim 1 (with its disclosure
 of R4 substituents and of X), provides an ipsis verbis disclo-
 sure of the subgenus claimed in the ’830 patent. Like the
 Board, we do not agree. Following this maze-like path, each
 step providing multiple alternative paths, is not a written
 description of what might have been described if each of
 the optional steps had been set forth as the only option.
 This argument calls to mind what Yogi Berra, the Yankee
 catcher, was reported to have said: “when one comes to a
 fork in the road, take it.” That comment was notable be-
 cause of its indeterminacy, its lack of direction. Similarly,
 here, all those optional choices do not define the intended
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 REGENTS OF THE UNIVERSITY OF MINNESOTA        v.                 9
 GILEAD SCIENCES, INC.


 result that is claim 1 of the ’830 patent.
     Moreover, Minnesota’s argument is akin to that re-
 jected in Fujikawa, where the applicant “persist[ed] in ar-
 guing that its proposed count [wa]s disclosed ipsis verbis in
 Wattanasin’s application.” Fujikawa, 

. As
 the court explained in Fujikawa:
       The basis for this contention seems to be that Wat-
       tanasin lists [a later-claimed substituent] as one
       possible moiety for R in his disclosure of the genus.
       Clearly, however, just because a moiety is listed as
       one possible choice for one position does not mean
       there is ipsis verbis support for every species or
       sub-genus that chooses that moiety. Were this the
       case, a “laundry list” disclosure of every possible
       moiety for every possible position would constitute
       a written description of every species in the genus.
       This cannot be because such a disclosure would not
       “reasonably lead” those skilled in the art to any
       particular species.
 

      The same is true here. The claims of P1 recite a com-
 pendium of common organic chemical functional groups,
 yielding a laundry list disclosure of different moieties for
 every possible side chain or functional group. Indeed, the
 listings of possibilities are so long, and so interwoven, that
 it is quite unclear how many compounds actually fall
 within the described genera and subgenera. Thus, we af-
 firm the Board’s decision that there is no ipsis verbis writ-
 ten description disclosure provided by P1 claim 47
 sufficient to support the ’830 patent’s claims.
                                B.
     As the Board noted in its final written decision, an ipsis
 verbis disclosure of a claimed subgenus is not necessary to
 satisfy the written description requirement of § 112. Fu-
 jikawa, 

. Thus, the Board next turned its
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 10               REGENTS OF THE UNIVERSITY OF MINNESOTA v.
                                       GILEAD SCIENCES, INC.


 attention to whether NP2-P1 provided sufficient blaze
 marks to provide written description support for the ’830
 patent claims. Decision at *9–10 (citing Ruschig, 379 F.2d
 at 994–95). As explained by the Board, “[t]hese blaze
 marks must be clear because ‘it is easy to bypass a tree in
 the forest, even one that lies close to the trail.’” Decision at
 *10 (citing Fujikawa, 

).
     The Board concluded that, “[i]n this case, we find the
 point at which one must leave the trail to find the tree is
 not well marked in P1 and NP2. Thus, P1 and NP2 do not
 provide sufficient written description support for the sub-
 genus of challenged claim 1.” Decision at *10.
      After failing to establish that P1 claim 47 constitutes
 an ipsis verbis disclosure, Minnesota attempts to recast
 this claim as a blaze mark. But again, similar to Fujikawa,
 even if P1 claim 47 “blaze[s] a trail through the forest” that
 runs close by the later-claimed tree, the priority applica-
 tions “do[] not direct one to the proposed tree in particular,
 and do[] not teach the point at which one should leave the
 trail to find it.” Fujikawa, 

. We conclude
 that the Board’s finding that NP2-P1 failed to provide suf-
 ficient blaze marks to support the ’830 patent’s priority
 claims was supported by substantial evidence.
     Minnesota further argues that the Board erred in fail-
 ing to consider the holdings in Ariad. In so doing, Minne-
 sota mischaracterizes Ariad as holding that merely
 “disclosing ‘structural features common to the members of
 [a] genus’ demonstrates possession of, and thereby sup-
 ports, the claimed genus.” Appellant’s Br. at 5. That is not
 what Ariad held.
      As the Board recognized, sufficiently describing a ge-
 nus under Ariad requires a description of a claimed genus
 disclosing either (1) “a representative number of species
 falling within the scope of the genus,” which the parties do
 not dispute is lacking here, or (2) “structural features com-
 mon to the members of the genus,” either of which must
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 REGENTS OF THE UNIVERSITY OF MINNESOTA       v.               11
 GILEAD SCIENCES, INC.


 enable “one of skill in the art [to] ‘visualize or recognize’ the
 members of the genus.” Decision at *4; Ariad, 

 (emphasis added). As indicated, the first requirement
 is not at issue here.
     As for the second, the Board addressed the question
 whether one of skill in the art would have been able to vis-
 ualize or recognize the members of the claimed genus by
 “search[ing] for blaze marks that guide a skilled artisan to
 the claimed subgenera.” Decision at *10. That was not er-
 ror. Regarding whether common structural features must
 exist between a claim and a putative priority disclosure,
 those features must constitute the near-entirety of the
 structures being compared. But the structures here are so
 extensive and varied that the structures of P1 claim 47,
 which, through its multiple dependencies, encompasses a
 significantly larger genus than that claimed in the ’830 pa-
 tent, are not sufficiently common to that of claim 1 of the
 ’830 patent to provide written description support.
      Finding no adequate blaze marks, the Board concluded
 that NP2-P1 do not provide sufficient written description
 to support the ’830 patent claims. Because NP3 provides
 the same disclosure as NP2, it too does not provide suffi-
 cient written description to support the ’830 patent claims.
 The Board thus determined that the claims of the ’830 pa-
 tent were therefore entitled to a priority date no earlier
 than March 28, 2014, making Sofia prior art to them. Re-
 garding the Board’s failure to address NP4, that is of no
 consequence. Even if NP4 did provide written description
 support for the ’830 patent claims, that application was not
 filed until January 29, 2013, and Sofia was published on
 January 21, 2010. Sofia would still be prior art. As the
 parties did not dispute that Sofia discloses each and every
 limitation of the ’830 patent claims, the Board found that
 the challenged claims of the ’830 patent were anticipated
 by Sofia. We agree.
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 12              REGENTS OF THE UNIVERSITY OF MINNESOTA v.
                                      GILEAD SCIENCES, INC.


                              II.
     Minnesota next contends that the Board ran afoul of
 APA requirements in several respects. We review Board
 decisions for compliance with the APA, setting aside “ac-
 tions of the Board that are arbitrary, capricious, an abuse
 of discretion, or otherwise not in accordance with law.” In
 re Sullivan, 

 (Fed. Cir. 2004); 

.
      First, Minnesota asserts that the Board failed to ad-
 dress key aspects of its expert’s testimony explaining why
 a skilled artisan would have understood NP2-P1 as de-
 scribing the claimed subgenus. According to Minnesota,
 this amounted to an APA violation. Gilead responds by as-
 serting that the Board did not ignore this testimony, and
 instead cited Minnesota’s expert more than a dozen times
 in its final written decision. It is within the discretion of
 the Board to weigh the evidence of record. Tiger Lily Ven-
 tures Ltd. v. Barclays Cap. Inc., 

, 1365−66
 (Fed. Cir. 2022); see also Shoes by Firebug LLC v. Stride
 Rite Child.’s Grp., LLC, 

, 1371 (Fed. Cir.
 2020) (“[I]t is not for us to second-guess the [Patent Trial
 and Appeal] Board’s assessment of the evidence.”). In this
 case, Minnesota appears to have wanted the Board to pro-
 vide an express “credibility determination or other fact-
 finding” concerning its expert’s testimony. Appellant’s Br.
 at 43. That is not required by the APA. Novartis AG v.
 Torrent Pharms. Ltd., 

 (Fed. Cir. 2017)
 (“The Board is not required to address every argument
 raised by a party or explain every possible reason support-
 ing its conclusion.” (cleaned up)). We find no abuse of dis-
 cretion or other action taken by the Board that is not in
 accordance with law.
     Minnesota next contends that the Board ignored a
 prior Board decision in a case involving a patent that Gil-
 ead owns that Minnesota views as facially inconsistent
 with this one. Gilead responds by asserting that that prior,
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 REGENTS OF THE UNIVERSITY OF MINNESOTA    v.               13
 GILEAD SCIENCES, INC.


 non-precedential final written decision, involving a differ-
 ent Board panel, considering a different patent and a dif-
 ferent record in a proceeding involving a different
 challenging party, finding different claims adequately sup-
 ported does not bind the Board to find written description
 support for the claims at issue here. We agree. The claims
 and alleged priority disclosures in that case are different
 from those here. See also Power Integrations, Inc. v. Semi-
 conductor Components Indus., LLC, 

 (Fed. Cir. 2019) (“[N]onprecedential Board decisions . . . do
 not even bind other panels of the Board.”).
      Finally, Minnesota contends that the Board applied its
 own procedural requirements inconsistently and arbitrar-
 ily in a way that permitted Gilead to unfairly submit new
 argument at the Reply stage of the IPR. Gilead notes that
 the Board provided Minnesota with an opportunity to re-
 spond to any alleged new arguments and that Minnesota
 has not identified any error or prejudice in how the Board
 treated these arguments. We agree with Gilead and find
 no APA violation.
                             III.
     Finally, Minnesota asserts that it is a sovereign state
 entity immune from IPR. Minnesota acknowledges that
 absent reversal en banc or by the Supreme Court, it is
 bound by the holding in Regents of the University of Minne-
 sota v. LSI Corp., 

 (Fed. Cir. 2019). Gilead
 responds that Minnesota had the opportunity to argue that
 sovereign immunity bars proceedings against it in the pre-
 vious Regents of the University of Minnesota proceeding, a
 case in which Gilead intervened. Gilead notes that this
 court has already rejected this argument and that the Su-
 preme Court declined to hear the case. Because this issue
 has been litigated to finality and determined on the merits,
 Minnesota is collaterally estopped from making an immun-
 ity argument here.
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 14              REGENTS OF THE UNIVERSITY OF MINNESOTA v.
                                      GILEAD SCIENCES, INC.


                        CONCLUSION
     We have considered Minnesota’s remaining arguments
 and do not find them persuasive. For the foregoing rea-
 sons, we affirm the Board’s final written decision holding
 that NP2 and P1 do not provide sufficient written descrip-
 tion to support the ’830 patent claims, and that Sofia there-
 fore anticipated these claims.
                        AFFIRMED